One of my main routes to/from the Higlands and one I always enjoy, with some twisty bits, fast screamers and wonderful scenery. Ive done the Craithe, Ballater and Dinnet routes as well, all are terrific.
But here, Id like to add to a suggestion to 2 other posted routes Alford - Cragellachie, Cragellachie - Granton-On-Spey that rounds out a circular route and great day out.
Instead of turning right at Colnabaichin towards Ballater, continue following the River Don towards Strathdon and Kildrummy Castle. Stop at Kildrummy Castle and take in the magnificent gardens (see photo) and yet another hot chocolate.

This is part of an alternative route to the A9 north (B9008 and A93 being the other parts). It takes you a bit out the way if your heading to Inverness but its well worth it. When I say out the way I only mean about 70km, its nothing for the scenery you will see and the roads are great but watch out for some of the corners.
There's also a Lecht ski center and a couple of cafes but no fuel stops until Braemar.

Have been on this route but from Crathie as opoosed to Ballater, well worth heading out from Ballater to the Crathie route as the road from Crathie is excellent.Mind out as some tight corners & also passing places on some of this route.